Bladder cancer can be subdivided into (1) superficial disease confined to the mucosa or submucosa and (2) muscle invading disease. Standard therapy for superficial disease consists of transurethral resection and intravesical chemotherapy (thiotepa, mitomycin C, BCG). Recurrence rates may range from 30%-85% depending upon the grade of tumor and multiplicity of lesions. Patients with high-grade in-situ in association with papillary tumor have a high frequency incidence of invasive disease developing within two years following resection alone. Five-year survival rates for patients developing muscle invasive disease (T2/T3A) range from 31%-52%. Early control of superficial disease offers a potential advantage towards reduction of the overall death rate in bladder malignancy. Carcinoma in-situ refractory to intravesical chemotherapy is a particularly troublesome clinical entity, as patients are at a high risk for the development of invasive disease and may require removal of the urinary bladder (cystectomy). Recent work with hematoporphyrin derivative (HpD) sensitized photodynamic therapy of the bladder mucosa suggests high cytotoxic effect, but low systemic toxicity. This modality may permit treatment of superficial carcinoma of the bladder as well as carcinoma in-situ which may permit bladder preservation with irradiation of tumor.